Issue for one breaking wind - critical moment (5,2,2,6)
I believe the answer is:
point of no return
'critical moment' is the definition.
'issue for one breaking wind' is the wordplay.
I cannot quite see how this works, but
'issue' could be 'return' ('return' can be a synonym of 'issue') and 'return' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
This explanation may well be incorrect...
(Other definitions for point of no return that I've seen before include "after which one's committed?" , "Crucial moment" , "After which one can't go back" , "ace played?" .)